BMW’s new aeroacoustics and e-drive center has started operations at the Research and Innovation Center (Munich).
The new building consists of two halves: In addition to a multifunctional part with workshop, testing and measuring facilities as well as a prototype construction for high-voltage batteries and inverters, the Aeroacoustics and E-Drive Center (AEZ) houses a technically and structurally new wind tunnel. According to the manufacturer, it is “the world’s largest acoustic wind tunnel with a vertical design and also the quietest”.
This means that the noise generated by the vehicle’s airstream can be precisely measured in the new wind tunnel. The facility is powerful enough to realistically test large vehicles such as the Rolls-Royce Phantom or the X7 luxury SUV. The wind tunnel is designed as an acoustic semi-free-field room. This means that, apart from the reverberant floor, there are no sound reflections. This makes it possible to realistically simulate the situation on the road. The frequency range for the semi-free-field conditions from 30 Hz covers the entire audible spectrum.
The acoustic wind tunnel is equipped with modern measurement technology to advance vehicle development. A 216-microphone acoustic camera enables the precise localization of disturbing noises with an accuracy of less than one centimeter. In addition, the wind tunnel has a laser vibrometry system with which the mechanical vibrations of the entire vehicle surface can be measured synchronously and without contact. A fully-fledged acoustic all-wheel roller test bench is also available.
The wind/rolling noise system makes it possible to separate the phenomena of rolling and wind (wind on/off, roll on/off). In addition, various modules such as a vehicle-accessible glass floor or a vehicle scale for motorcycles can be exchanged in a short time without having to move the vehicle. This allows developers to test different configurations quickly and efficiently.
The entire building, from the three-meter-thick base plate to the façade, is acoustically insulated against noise from the surroundings. The wind tunnel was designed to be upright so that the building site is used efficiently. This was the only way to fully meet all the requirements for both buildings and realize them on the available space.
The AEZ houses workshops, test and measuring stands as well as prototype lines. The focus here is also on electromobility. The company builds and tests prototypes of future high-voltage batteries for electric vehicles here. In another area, inverters for future electric motors are produced on a pilot line under clean room conditions.
